Apparatus for producing hollow glass objects

ABSTRACT

Prior to introducing a body of fluid glass into a split mold, the wall of the mold cavity, closed except for a charging opening, is sprayed with an atomized lubricating and parting agent from a nozzle operated by means of compressed air, thereby avoiding deposition of the agent on the engaging faces of the mold sections and the resulting surface defects in the shaped glass object.

United States Patent 1191 APPARATUS FOR PRODUCING HOLLOW GLASS OBJECTS [75] Inventor: Hans-Dieter Renkl, Herrlingen, I

Germany [73] Assignee: Deutsche Acheson GmbH, Ulm,

Germany [22] Filed: Aug. 16, 1972 [21] Appl. No.: 281,045

[30] Foreign Application Priority Data Aug. 18,1971 Germany 2141455 [52] US. Cl. 265/169, 65/26, 65/208- [51]- Int. Cl. C03b 39/00, C03b 5/30 [58] Field of Search 65/161, 169, 24, 26, 208

[56] References Cited UNITED STATES PATENTS 7/1964 Keller; 65/169 X 5] Apr. 2, 1974 3,523,016 8/1970 MattUS 65 26 x 3,580,711 5 1971 1111111111611 3,721,542 3/1972 K6061 1,756,493 4 1930 Peiler 3,672,860 6/1972 Keller 65/24 Primary Ex aminerFrank Miga ABSTRACT "Prior to introducing a body of fluid glass into a split tions and the resulting glass object.

mold, the wall of the mold cavity, closed except for a charging opening, is sprayed with an atomized lubrieating and parting agent from a nozzle operated by means of compressed air, thereby avoiding deposition of the agent on the engaging faces of the mold secsurface defects in the shaped 2 Claims, 14 Drawing Figures plural molds.

APPARATUS FOR PRODUCING HOLLOW GLASS OBJECTS This invention relates to the production of hollow glass objects, and particularly to a method of producing such Objects and to apparatus for performing the method.

It is known to introduce a fluid body or blank of glass into a split mold whose sections, when sealingly engaged with each other, jointly define a continuous wall bounding the mold cavity and formed with a charging opening for receiving the glass to beshaped.

To improve the surfacefinish of the ultimately produced glass body, the cavity wall needs to be coated with a lubricating and parting agent which wets the wall, facilitates distribution of the glass mass along the wall and the removal of the sufficiently solidified glass body from the mold.

It has been common practice to coat the cavity wall while the mold sections are separated from each other after withdrawal of a previously molded glass object. In this position of the mold sections, the surfaces of the sections which are sealingly engaged in the operative position of the mold are also exposed, and the lubricatfaces of the mold sectionswithin a few molding cycles to prevent preciselyconforrning engagement of the sections so that a thin gap is left between the sections and is reproduced as a ridge or heavy parting line on the molded glass object.

A primary object of the invention is the provision of a method which avoids accumulation of residues from lubricating and parting agents on the engaging surfaces of the sections in a split mold. Another object is the provision of apparatus suitable for performing the method in a glass forming apparatus having single or With these and other objects in view, the invention, in one of its more specific aspects, resides in a method of producing a glass object in a mold constituted by a plurality of sections movable toward and away from an operative position in which the sections sealingly engage each other and jointly constitute a continuous wall formed with a charging opening and bounding a cavity. V

According to the method of the invention, the mold sections are first moved into the operative position and thereafter sprayed with a finely dispersed lubricating and parting agent in an amount sufficient to wet the mold wall. A body of fluid glass is introduced into the mold cavity through the opening and subjected in the cavity to mechanical stress until it conformingly engages the wetted wall and is shapedthereby. Contact with the wall may also sufficiently solidify the glass. After the sections have been moved away from 'each other, the shaped body of glass is removed. from the cavity, and is free of the surface defects that'would have been caused if precise engagement of the mold sections had been prevented by a residue of lubricating and parting agent on the engaged sectionfaces.

The apparatus employed for performing the aforedescribed method includes moving means for moving the mold sections toward and away from each other. A feed mechanism is provided for releasing a body of glass into th'e'cavity. A spraying mechanism communicates with a source of the lubricating and parting agent and includes a nozzle outside the cavity directed toward the mold opening in such a manner that it may spray the agent in finely dispersed condition into the cavity.

Other features, additional objects, and many of the attendant advantages of this invention will readily be appreciated as the same becomes betterunderstood 'from the following detailed description of a preferred embodiment of the invention when considered in connection with the appended drawing in which: FIG. 1 is a fragmentary,,elevational, and partly sectional view of a bottle blowing machine of the invention;

FIGS. 2 to 5 show the machine of FIG. 1 in consecutive positions assumed during a blowing cycle;

FIG. 6 is an elevational fragmentary view of-a greater portion of the bottle blowing machine and includes a schematic circuit diagram of an electric control'circuit for the machine and FIGS. 7 to 14 further illustrate the operation of the apparatus 'of'FlG. l in the manner of FIGS. 2 to 5 Referring now tothedrawing, and initially to FIG. 1, there is shown only as much of a bottle blowing ma-' chine as is needed for an understanding of' the basic method aspects of this invention. The" upright inner wall of a split mold 11 is formed by two sections 11a,

11b, each of which may be moved'horizontally toward and away from the other section by a mechanism, con ventional in itself, and indicated in the drawing only by a double arrow 110. A stationary,'tubular plug 17 constitutes the bottom of the mold 11 in the operative position of the mold sections 11a, 11b shown in FIG. 2 in which the mold is closed in all directions except for an upwardly directed charging opening 11d. 5.

Molten glassmay be supplied to the mold 11 by gravity from a non-illustrated and conventional furnace through an oblique chute 12 whose lower ehd is located vertically above the opening'l ldsMete rin'g devicesassociated with the chute l2 and the nonillustrated furnace determine the size of the glass glob 13 (FIG. 4) which is dropped from the chute-12 into the mold 11 from time to time, as is not novel in itself.

According to the invention, a spray nozzle 16 is fixedly mounted above the mold opening 11d in such a manner that the nozzleorifice 15 is closely adjacent the end 14 of the chute 12' and directed obliquely toward the opening lld. A lubricant line 21 and a compressed air line 22'communicate with the atomizer head 18 of the nozzle 16 and serve as respective sources of lubricating andparting agent and of gas under pressure respectively. The agent in the line 21 is replenished by gravity or otherwise from a nonillustrated storage tank under a pressure sufficient merely to deliver the lubricating and parting agent to the throat of the atomizing head 18 for dispersion of small droplets by a stream of compressed air provided from a non-illustrated compressor or storage tank by the line 22, and controlled bya solenoid valve 19 in the line 22. The lubricating and parting agent does not flow from the line 21 until the valve 19 is opened by electric current energizing the coil of its solenoid.

FIG. 1; shows the afore-described apparatus in the condition'after completion of a'molding cycle and removal of the molded bottle from the separated sections 11a, 11b of the mold 11. In the new molding cycle, the mold sections are moved into the operative position illustrated in H6. 2. Thereafter, the solenoid of the valve 19 is energized, and a jet 30 of air carrying suspended droplets of the atomized lubricating and parting agent is discharged from the nozzle-orifice l5. Uniform distribution of the agent and wetting of the interior mold wall are facilitated by simultaneously connecting the bore of the plug 17 with a vacuum line, commonly employed in this art and not specifically illustrated. I

A glass glob 13 is dropped from the chute 12 into the coated mold cavity, as shown in FIG. 4, and expanded by compressed air admitted through the plug 17 until, it becomes hollow and conforms to the wall of the, cav-- ity. A cover, not shown, is simultaneously clamped over the opening 11d so thata bottle orbottle blank 20, seen in FIG. 5, may be removed from the mold when the moldsections, 11a, 11b, are moved apart, whereby the condition of FIG. 1 is restored.

While the molding cycle of the machine has been described so far'with reference to a single mold 11, the machine has a multiplicity of molds arranged on a common support, and FlGI 6 in part illustrates devices mounted on the support which itself has been omitted furnace or holding tank-through respective metering devices, not shown. p

'Only a continuously rotating drive shaft 25 of the control mechanism for the glass metering devices and of the mold opening and closing mechanism is seen in FIG. 6. it carries a radial cam 23 which engages the actuating member ofa normally open switch 24 once during each revolution of the shaft 25. The switch 24 is arranged in a series circuit with a first stepping switch 31 a second stepping switch 26 and a source of electric current, not shown. Temporary closing of the switch 24 causes a pulse to be generated in the series circuit, and the switch 31 to be advanced one step, In selected steps; as will presently be explained, the switch 31 transmits the received pulse to the second stepping switch 26, and the transmitted pulses are sequentially 'disbributed'by the switch 26 to six paralleldelay circuits 27vrespe ctively associated with the'six molds 11.

The delayed output pulse of each circuit 27 is transmitted to a timing relay 28 whichQupon receipt of each .pulse, feeds current from a non-illustrated source through a third stepping switch- 29 to the solenoid valves :19 respectively. The duration of each valve opening can be set on the relay 28 by a control knob 28'.

4' The shaft 25 makes six revolutions during each molding cycle. When it'is desired to coat each mold 11 after each cycle, the stepping switch 31 is wired to the switch 26 to transmit each pulse of the switch 24. When it is sufficient to coat each mold 11 after several bottles were produced therein, some of the terminals of the switch 31 remain unconnected so that only certain pulses generated'by the switch 24 are automatically selected by the switch 31 and transmitted to produce the desired intermittent coating operation. 1

Regardless of the selection and spacing of pulses brought about by the switch 31, the switch 26 sequentially transmits the pulsesto the delay circuits 27. The circuits are chosen in such a manner as to compensate for differences in the characteristics of the glass feeding mechanism associated with the molds 11. The chutes 12 are normally of different length to bridge different distances from the non-illustrated furnace, causin'g'a shift-in the entire molding cycle for the associated mold. The delay circuits 27 permit the moment of lubricating'and parting agent discharge to be precisely adjusted for the characteristics of the associated mold arrangement. I v

A- typical rnold lubricating and parting agent commonly used in this art is a colloidal solution of dellocculated Acheson graphite inwater. An amount of this agent sufficient for coating the mold for a 32 oz. bottle may be released from the nozzle 16 in 0.3 to 0.4 seconds under an air pressure of approximately to p.s.i.gl For highest machine capacity, the time between the closing of the mold and the charging of the mold with glass should not be greater than one second,*and the opening of each valve 19 must be timed precisely to fit into this short period; This is made possible by the delay circuits 27.

FIGS. 7 to 14 show in more detail the operation of a glass molding apparatus of this invention' In FIG. 7 one can see after a moldingcycle an open mold consisting of two mold parts 110a, 1101;. Further, the mold comprises a lower mold part 130 which consists of' two halves 130a, 130b. The halves 130a, 1301) are movable in a horizontal direction and the same is true for the two mold parts 110a, 110b. Above; the mold 1l0'there is provided a chute 112 the lower end of which isdes'ignated by 114L'Adjacent thelower end'114 of the chute 112 there is provided a spraying device 116 which comprises a spraying head 118 and a spraying nozzle 120. The spraying head 116 is connected to a source of air pressure by a line 122 containing a valve 128 and to a source of lubricating and parting agent by a'line 124 including a valve 126.

operation-the mold parts 1101:, 110b and the halves 130a, 13Gb have been brought into the closed position and a drop-in-ring 132 has been positioned over the inlet opening 138 of themold so that the mold is now prepared for being filled with a charge of molten glass.

In FIG. 9 a lubricating and parting agent is introduced through thespr'aying nozzle and the drop-inring 132 into the mold 110. It should be noted that the drop-in-ring 132 is movable between its operative position as shown in FIGS. 8 and 9 and an inoperative position not shown along a horizontal path of movement.

In FIG. 9 one can see a line 150 which is connected to a vacuum source. Said vacuum source is connected to the lower mold part 130. By thisline 150, which contains a valve 151, a vacuum can be applied to the mold chamber of the mold l 10 when the spraying nozzle 120 sprays lubricating and parting agent into the mold. By maintaining a vacuum within the mold chamber of the mold 110 a uniform distribution of the lubricating and parting agent within the mold can be achieved in spite of the fact that the spraying nozzle 1 has a considerable. distance from the inlet opening 138 of the mold 110.

FIG. 10 shows the moment of operation in which a droplet of molten glass 134 is falling through the dropin-ring 132 and the inlet opening 138 into the mold chamber of the mold 110. At the same time air contained in the mold chamber may be withdrawn therefrom through the lower mold part 130 and the vacuum line 151 as illustrated in FIG. 9.

In FIG. 11 an upper mold head 136 has been placed upon the drop-in-ring l32. This upper mold head 136 is connected to a pressure air source so that pressurized air is admitted through the inlet opening 138 into the tion:

mold chamber. The pressurized air presses the drop of molten glass 134 into the position as illustrated in FIG. 11.

FIG. 12 shows the moment of operation in which pressurized air is admitted via the lower mold part 130 into the mold chamber. By this pressurized air the droplet 134 is formed into a hollow body 142. For this operation the drop-in-ring 132 has been removed and the upper mold head 136 has been placed immediately on the inlet opening 138.

In FIG. 13 the mold has been opened again by removing the mold parts 110a, 1101) from each other and moving the halves 130a, lb away from each other so that the hollow body 142 can be removed now.

The removal of the hollow body 142 is illustrated in FIG. 14 which is a view of the device as illustrated in FIGS. 6 to 13 when regarded in the direction of the arrows XIV XIV.

In FIG. 14 one can see again the mold 110 and-associated therewith an object removing mechanism which comprises a swivel arm 146 and mounted to the outer end of this swivel arm 146 a gripping device 144. The

swivel arm 144 is pivotally mounted on an axis A. The gripping device 144 grips the lower end of the hollow body 142 when the mold parts 110a, 1l0b and the halves 130a, 130b have been removed from each other. Hereupon the swivel arm 146 with the gripping device 144 and the hollow body 142 move from the position path of the swinging movement of the swivel arm 1 46, gripping device 144 and hollow body 142. The lower end 114 of the chute 112 and the spraying nozzle 120 are placed in such a distance from the upper end of the mold 110 that they do not interfere with said movement illustrated by circle K. It is to be noted that the spraying nozzle is provided at a location in which no movement of the spraying nozzle is necessary for allowing the removal of the hollow body fromthe mold so that no time is lost during an operation cycle for the movement of the spraying nozzle between an operating and a non-operating position. It is further to be noted that the spraying nozzle 120 is at a place remote from the mold so that no high temperatures can occur at said nozzle which could lead to a baking of solids of the lubricating and parting agent at the spraying nozzle.

Aqueous graphite suspension has been found to be the most suitable agent for being used in connection with the'apparatus and the process of this invention.

What is claimed is: 1. A glass molding apparatus comprising, in combinaa. a mold constituted by a plurality of sections;

b. moving means for moving said sections toward and away from a'position in which said sections sealingly engage eachother and jointly constitute'a continuous wall formed with an upwardly directed opening, said wall bounding'a cavity in the mold;

c. feed means for delivering a bodyof fluid glass into said cavity by gravity said feed means including a chute member downwardly inclined toward said opening and having a lowermost portion spaced from said opening in a vertically upward direction;

(I. a source of a liquid lubricating and parting agent;

fixedly mounted in upwardly spaced relationship to said'opening,

2. said nozzle having a spraying orifice closely adjacent said lowermost portion and directed toward said orifice obliquely to the vertical direction of delivery of said body of fluid glass.

2. An apparatus as set forth in claim 1, further comprising suction means, said mold, when in said position, having a bottom downwardly spaced in said cavity from said opening, said suction means including a conduit terminating in said bottom for evacuating said cavity during delivery ofv said atomized agent from said ori- 

1. A glass molding apparatus comprising, in combination: a. a mold constituted by a plurality of sections; b. moving means for moving said sections toward and away from a position in which said sections sealingly engage each other and jointly constitute a continuous wall formed with an upwardly directed opening, said wall bounding a cavity in the mold; c. feed means for delivering a body of fluid glass into said cavity by gravity, said feed means including a chute member downwardly inclined toward said opening and having a lowermost portion spaced from said opening in a vertically upward direction; d. a source of a liquid lubricating and parting agent; e. a source of gas under pressure higher than atmospheric pressure; and f. atomizing means connected to said sources for atomizing said agent in said gas, and for delivering the atomized agent to said cavity through said opening;
 1. said atomizing means including a spraying nozzle fixedly mounted in upwardly spaced relationship to said opening,
 2. said nozzle having a spraying orifice closely adjacent said lowermost portion and directed toward said orifice obliquely to the vertical direction of delivery of said body of fluid glass.
 2. said nozzle having a spraying orifice closely adjacent said lowermost portion and directed toward said orifice obliquely to the vertical direction of delivery of said body of fluid glass.
 2. An apparatus as set forth in claim 1, further comprising suction means, said mold, when in said position, having a bottom downwardly spaced in said cavity from said opening, said suction means including a conduit terminating in said bottom for evacUating said cavity during delivery of said atomized agent from said orifice. 